Problem: The arithmetic sequence $(a_i)$ is defined by the formula: $a_i = -7 - 2(i - 1)$ What is $a_{5}$, the fifth term in the sequence?
From the given formula, we can see that the first term of the sequence is $-7$ and the common difference is $-2$ To find $a_{5}$ , we can simply substitute $i = 5$ into the given formula. Therefore, the fifth term is equal to $a_{5} = -7 - 2 (5 - 1) = -15$.